Decommissioning Trust Funds (Schedule of Available-for-Sale Securities Reconciliation) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	$ 2,051.0	$ 1,770.0
Debt Securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale, Unrealized Loss Position	94.0	134.0
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	36.0	19.0
Debt Securities, Available-for-Sale	2,051.0	1,770.0
Entergy Arkansas [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	597.5	496.9
Entergy Arkansas [Member] | Debt Securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale, Unrealized Loss Position	42.3	53.6
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	7.5	2.4
Debt Securities, Available-for-Sale	597.5	496.9
Entergy Louisiana [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	877.6	788.1
Entergy Louisiana [Member] | Debt Securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale, Unrealized Loss Position	25.0	37.4
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	16.6	11.7
Debt Securities, Available-for-Sale	877.6	788.1
System Energy [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	575.9	485.2
System Energy [Member] | Debt Securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale, Unrealized Loss Position	26.6	42.5
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	12.3	4.5
Debt Securities, Available-for-Sale	$ 575.9	$ 485.2